I added them to https://gametz.com/Signaturator.html
But, you'll soon see that there are issues with fonts being hard to read and alignment.
I have a few things I can tweak. I changed the font to white instead of black for the first 2 and this helped GCPinkBlack the most. GCChecks is going to be tough, though. I'm not sure that will be doable. GCSunset doesn't look too bad, but the text overlaps the bar thing in the middle and I don't think there's room to squish it under that -- I can try (many of the old ones have special alignments that I had to figure out by hand).
If you have a way to keep the general location of things similar to an existing background, that would help me a lot. Otherwise, I have to spend a lot time trying to find the right placements and such.
It's also worth noting that I don't think many people actually use this. So, this is "just for fun" ...